Drainage systems for the removal of surface water are well known. Initially, such systems were made entirely of concrete or clay piping in conjunction with either a field poured or precast concrete receptacle or drainage inlet. The inlet-to-pipe connection has been made by several means, including grouting or various types of rubber gaskets.
More recently, various types of alternative piping and structure materials have been utilized including polyvinylchloride (PVC), high density polyethylene (HDPE) an acrylonitrile butadiene styrene (ABS), due to their light weight and ease of installation.
However, it has been discovered that drainage inlets made of these various alternative materials are problematic for many installations. For example, a plastic drainage inlet can easily be broken if it is inadvertently hit by vehicles or maintenance equipment such as lawn mowers or roto-tillers. Therefore, concrete inlets are still frequently used because of the increased strength and durability of concrete. For example, a precast drain inlet is disclosed in U.S. Pat. No. Des. 280,126. However, such inlets are typically connected to piping by field poured concrete or grouted methods.
It would be desirable if a precast concrete drain inlet were capable of being pre-manufactured in such a way as to provide an effective connection or seal with plastic riser pipes, thereby eliminating the need for grouting or field pouring. This would offer the flexibility and ease of installation of the plastic materials while also offering the durability of concrete.